In DE-OS No. 2,816,836, dated Oct. 26, 1978 there are described cyanoacrylate adhesive compositions which employ crown ethers as polymerization accelerators. Such compositions are useful for bonding acidic surfaces such as wood which inhibit cyanoacrylate polymerization.
Crown ethers, however, are known to be very toxic, the reported effects of exposure including damage to the central nervous system and testicular atrophy. Leong, B. K. J., Chem. Eng. News, 53, 5(1975). Furthermore, such accelerators are reportedly very difficult to synthesize, supplying the desired product in only low yields because of the tendency to produce intermolecular linkages. Accordingly, there is a need for alternative cyanoacrylate accelerators suitable for wood bonding applicators.
In U.S. Pat. No. 4,170,585, there are described cyanoacrylate compositions in which certain polyethylene glycols poly(ethyleneoxy) functional surfactants act as wood bonding accelerators. Such compounds, however, have the reported disadvantage that they to contain water and other difficult to remove substances which spontaneously initiate polymerization of the cyanoacrylate monomer.
U.S. Pat. No. 4,377,490 discloses mixtures of aromatic and sliphatic polyols and polyethers said to improve initial strength of cyanoacrylate wood bonding products.
U.S Pat. No. 4,386,193 discloses certain 3 or 4 arm polyol podand compounds as alternatives to crown-ether accelerators. Japan Kokai Tokkyo Koho No. 82-70171, suggests the use of certain polyorganosiloxane compounds which include polyether substituents as additives for wood bonding cyanoacrylate compositions.
Chem. Abstracts, 97 145913n reports the use of a hydroxy-terminated poly(dimethylsiloxane) in fast bonding cyanoacrylate compositions.
DE-OS No. 3,006 071 discloses certain furan derivatives as co-accelerators with crown ethers in cyanoacrylate compositions.